Machining center employing cam operated tool changer

ABSTRACT

A machining center wherein rotating tools are cammingly interchanged between a tool carrier and tool bearing as a direct function of tool carrier movement.

[ Dec. 25, 1973 United States Patent [1 1 Cupler, II et al.

[ MACHINING CENTER EMPLOYING CAM 3.263.300 8/1966 Schatzman et OPERATEDTOOL CHANGER 3 533 306 10/1970 Link....,....

[75] Inventors: John A. Cupler, II, 10 Cupler Dr.,

Cumberland; Wayne B. Stone, Jr., Bethesda, both of Md.

FOREIGN PATENTS OR APPLICATIONS l4,944 9/l897 Germany 408/35 PrimaryExaminerAndrew R. .Iuhasz Assistant ExaminerZ. R. BilinskyAttorney-Colton & Stone ABSTRACT [52] U S Cl. 29/26 A, 29/568, 408/35[51] Int. B231] 3/157 [58] Field of Search...................... 29/26A, 568,44;

408/35 A machining center wherein rotating tools are camminglyinterchanged between a tool carrier and tool References cued bearing asa direct function of tool carrier movement. UNITED STATES PATENTS3,478,419 29/568 17 Claims, 7 Drawing Figures PATENTED UEBZS I975 SHEH 10F 3 INVENTORS. JOHN A. CUPLER,]I WAYNE B. STONE, JR.

FIG. 2

ATTORNEYS.

PATENTED I 3,780,406

SHEEI 2 BF 3 lflllvllllllllllnn I m mi JOHN A. CUPLER,]I WAYNE B. STONEJR- BY cheap/4;,

ATTORNEYS.

IN VENTORS.

PAIENIED [E825 I975 SHEETJUFS HHYIWI INVENTORS.

JOHN A. CUPLER,I WAYNE B. STONE, JR.

Qua/Ag;

ATTORNEYQ MACHINING CENTER EMPLOYING CAM OPERATED TOOL CHANGER Thedisclosure relates, primarily, to machining centers of the typeemploying automatic or semi-automatic tool changers and is hereindescribed in connection with machining centers employing open bearingsand non-captive tools. A non-captive tool is herein defined as one whichmay undergo bodily movement, transversely of its own axis, relative toboth the tool bearing structure which supports the tool in workingposition and a tool carrier which supports the tool in a nonworkingposition.

BACKGROUND OF THE INVENTION The public introduction of the machiningcenter disclosed in U.S. Pat. No. 3,478,4l9 in 1969 marked the advent ofa new concept in tool changing operations; that of the non-captive tool.The elimination of that down time inherently associated with too]changing cycles as practiced with chucked tools made it possible toroutinely effect tool interchange cycles within time periods of 0.5 3seconds depending upon the size tools involved. This was made possibleby the direct interchange of tools between the bearing and tool carrierwithout the intermediary of a separate tool change element to remove atool from the carrier and place it in a bearing and, also, without thenecessity of performing chucking and unchucking operations ordiscontinuance of the tool drive. A complete background discussion ofthe basic differences and advantages inherent in noncaptive toolchangers vis-a-vis conventional chuck type tool changers appears in theaforesaid US. Pat. No. 3,478,419 whose disclosure is herein incorporatedby reference. As will be appreciated from an inspection of the aforesaidpatent disclosure; the machining center therein described is quitesophisticated and, consequently, relatively expensive. Although suchprior noncaptive tool changers have not required a disruption of thetool drive during a tool change cycle it has been necessary todisconnect the tool drive from the tool to permit the tool carrier toundergo a variable, compound path of movement relative to the bearing inorder to effect tool interchange which requires a somewhat complex toolinput drive mechanism as well as various synchronizing controls anddrive mechanisms to produce the necessary compound movement of the toolcarrier.

SUMMARY OF THE INVENTION The primary purpose of the invention is toprovide a machining center employing an extremely simple tool changemechanism which, basically, involves a single moving part; the toolcarrier. Tools may thus be interchanged with a tool bearing as a directfunction of tool carrier movement while the interchanged tools arerotating at full R.P.M. The tool changer is equally susceptible ofmanual, semi-automatic or fully automatic operation and is effected bymovement of the various tool stations on the tool carrier along acommon, uniform path. The path of movement undergone by tools supportedat the tool stations is intersected by fixed cam surfaces merging withthe open portion of the bearing so that movement of the tool carrier iseffective to cam tools into and out of the open bearing; the nonworkingtools acting as idlers for an extensiblerecirculating drive belt whichaccommodates the slight relative movement of the interchanged toolsrelative to the tool carrier.

The word tool, as used herein, refers not only to the working portion ofth tool itself but also to its supporting spindle as is commonterminology in connection with non-captive tools. It will be apparentthat the working end portion of the tool could be formed separately andmounted on the spindle or formed integrally therewith.

Each of the tool carrier stations comprise a slot extending into thecarrier whose depth exceeds the relative movement of a tool undergoing acamming interchange with the bearing so that all of the tools arecontinually positioned for engagement by the tool carrier for movementtherewith in the direction of carrier movement. The closed ends of theslots include releasable tool supports for retaining the tools at suchposition prior to and following their working positionment on the openbearing at which time the working tool is held outwardly from thereleasable tool support position but still within the slot. Thus thetool stations are mounted for movement along a common, uniform pathadjacent the bearing and the releasable tool supports provided at eachstation define tool support axes which are, similarly, movable along acommon uniform path which is parallel to the uniform path of toolstation movement. The tools which are positioned at each station arereleasably supported with their axes coincident with the tool supportaxes defined by the releasable tool supports throughout a major portionof the uniform path of movement undergone by the releasable toolsupports but are cammingly diverted therefrom over a minor portion oftheir conjoint paths of movement. Thus, the tool stations and releasabletool supports follow a common uniform path throughout the total range ofmovement of the tool carrier while the tools positioned at the toolstation follow a common, non-uniform path of movement. The expressioncommon, uniform path is used in its usual sense to indicate a lack ofvariation throughout the total path length along which each of aplurality of elements are movable. The non-uniform path of movementundergone by the tools results from their camming movement into and outof the tool bearing.

An extensible drive belt is in constant driving engagement with at leasttwo tools adjacent the bearing to bias the same in the direction of thereleasable tool support position.

DESCRIPTION OF THE DRAWINGS FIG. I is a top plan view of a machiningcenter constructed in accordance with the present invention;

FIG. 2 is a broken, enlarged top plan view similar to FIG. 1 butomitting the infeed mechanism for clarity of illustration;

FIG. 3 is a front elevational view of the open bearing and associatedtool change mechanism;

FIG. 4 is a partly sectioned view taken along line 4-4 of FIG. 3;

FIG. 5 is a view similar to FIG. 2 but illustrating a different toolcarrier position;

FIG. 6 is a cross-sectional view taken along line 66 of FIG. 5; and

FIG. 7 is a fragmentary top plan view of a modified releasable toolsupport.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The machining center is bestillustrated, in its entirety, in FIGS. 1, 3 and 4. A fixed standard 12having integrally mounted thereon an open bearing 14, herein illustratedas a Vee bearing, is rigidly mounted on any desired support such as awork table, not shown. A tool carrier 16 comprising a pair of annularplates 18 rigidly interconnected by interplate connectors 20 is mountedfor rotation about an axis 22 by a plurality of flanged idler rollers 24mounted on upper and lower bracket plates 26, 28 secured to standard 12and engaging the inner peripheries 30 of upper and lower plates 18. Theouter periphery 32 of tool carrier 16 is slotted to form a plurality oftool stations 34. The radially innermost end of each tool station 34includes releasable tool support means defining a tool support axis 36which, in the case of the non-working tools 38, 40, 42 positioned asshown in FIG. 2, will be coincident with the tool axis. In the case ofthe working tool 44 positioned as shown in FIG. 2, the tool is inbearing engagement with Vee bearing 14 whose bearing surfaces define aworking tool axis 46 which is radially outwardly spaced from thereleasable tool support axis 36. The releasable tool support axis 36 isdefined at each station by Vee bearing surfaces 48 formed at theradially inner end of each tool station and, in the embodiment of FIG.1-6, cooperating permanent magnets 49, flush with each bearing surface48, are provided to maintain a tool in coincident axial alignment withaxis 36 until the same is cammed radially outward therefrom by cammingmeans associated with the Vee bearing. Each tool station 34 is definedby a pair of slots; i.e., aligned upper and lower slots in the rigidlyinterconnected upper and lower plates 18 as clearly shown in FIG. 4.

An extensible recirculating drive belt 50 of the type disclosed in U.S.Pat. No. 3,533,225 is drivingly engaged with the drive pulley of a motor52 and at least three of thee tools on tool carrier 16 by virtue of thefrictional driving engagement with tool spindles 54.

Oppositely directed upper and lower cam pairs 56, 58 positioned oneither side of bearing 14 cooperate with the sides 60 of each of theslots forming the tool stations to directly cam tools into and out ofVee bearing 14 as a single function of tool carrier movement. The campairs 56, 58 are rigidly mounted to the upper and lower Vee sections 62,64 comprising the composite Vee bearing 14 and one end of the outer camsurfaces thereof merge smoothly with wall portions 66 on either side ofeach Vee section which wall portions, in turn, merge smoothly with eachof the Vee sections. The other ends of the cam surfaces intersect therotary path of movement undergone by tools 38, 40, 42, 44 as the toolcarrier is rotated about axis 22.

A plurality of tool positioning posts 68 rigidly secured to lowerannular plate 18 ensure that the drive pulley 54 of each tool positionedon the tool carrier will lie in the same plane as does the recirculatingdrive belt 50 except during that period of time when the particular toolis in working position at which time the tools may undergo areciprocating infeed motion as imparted thereto by the usual push rod 70of a conventional manual infeed mechanism 72 of that type conventionallyemployed with Vee machining centers and more particularly described inthose technical bulletins published by National Jet Company, Cumberland,Maryland under the catalog designation M2-269, M3-668 and M7-967. Eachtool positioning post 68 is positioned adjacent a tool station 34 andcomprises a lower stud 74 mounted on lower plate 18 and an uppertelescoping sleeve 76 normally biased to a fully extended position by aspring 78 against an internal extension limiting stop, not shown. A toolpositioning arm 80 integral with sleeve 76 is adapted to engage theundersurface of a knurled ring 82 integral with each tool. Aternatively,the ring 82 could be omitted and arm 80 positioned to engage theundersurface of tool drive pulley 54. In either event it will beapparent that positioning posts 68 act to resiliently bias each of thetools to the upper positions shown in the drawings.

The particular compound configuration of the interplate connectors is topermit passage of the same past Vee bearing 14 while yet insuring thatthe run of the recirculating drive belt 50 is unimpeded at all times.Thus the upper and lower bight portions 84 of each interplate connectorare dimensioned to pass, with clearance, past the upper and lower Veebearing sections 62, 64, respectively, while the central reverselydirected bight portion 86 extends radially inward a sufficient distanceto insure that the straight line run of dirve belt 50 between adjacenttools is always positioned radially outward thereof as will be apparentfrom an inspection of FIGS. 2 and 5.

As previously stated, the machining center is adapted for manual,semi-automatic or fully automatic operation and is herein specificallyillustrated for semiautomatic and manual operation. A ring rack 88 isrigidly secured to the undersurface of the lower annular plate 18 and astepper motor 90, rigidly mounted on standard 12, has a pinion 92secured to the output shaft thereof positioned in meshing engagementwith rack 88. Intermittent energization of motor by either a manuallycontrolled switching arrangement or a conventional tape program controlresults in the intermittent or stepped rotation of tool carrier 16 tocam one tool out of bearing 14 and can another tool into bearingengagement therewith.

Thus, in operation and assuming the completion of a work operation by atool 44 positioned as in FIG. 2; energization of motor 90 results in theclockwise rotation of tool carrier 16 which, in the specific exampleherein illustrated, will be continuous through an arc of 90. Uponinitial rotation of carrier 16, the side wall 60 of the slotted toolstation engages tool 44 and the same is cammed radially outward alongthe left incline (as viewed in FIG. 2) of Vee bearing 14 until itreaches surface 66. The tool is then moved along surface 66 by thecontinued rotation of carrier 16 and, then, down the inclined surfacesof the upper and lower left side cams 56, 68, as viewed in FIGS. 2 and3. The path of movement described by the tool axis 46 of each tool as itis cammed into and out of Vee bearing 14 is illustrated by the brokenline 94 in FIG. 5 and the just described movement of tool 44 out ofbearing 14 followed that portion of broken line 94 to the left of Veebearing 14 as viewed in FIG. 5. Inasmuch as the extensible drive belt 50is constantly under tension, tool 44 is biased radially inward towardthe inner end of its associated tool station and the tool support axis36 defined thereby, at all times. Upon reaching the leftmost ends ofcams 56, 58 tool 44 is urged full against the Vee bearing surfaces atthe inner end of the tool station and into axial alignment with toolsupport axis 36 whereupon it is releasably retained by magnets 49 whilethe associated positioning post 68 insures that spindle 54 will notbecome misaligned with drive belt 50 when the tool moves out ofengagement with the drive belt upon reaching the position of tool 40 inFIG. 2. Following the removal of tool 44 from bearing engagement withVee bearing 14 and its repositionment at the inner end of tool station34, as just described; further rotation of carrier 16 brings tool 42into intiial engagement with the right hand upper and lower earns 56,58. This is the position of FIG. 5. The tool is thus cammed outwardlywith its axis following the dotted line 94 until the same bottoms in Veebearing 14 at which time it is held outwardly of the Vee bearing surface48 on the tool station by virture of its bearing engagement with bearing14. The working tool may then be infed relative to bearing 14 in anydesired manner conventional to the non-captive tool art. The infeedmechanism herein illustrated involves a manual manipulation of handle 96to reciprocate push rod 70 however a fully automated cone cam infeedmechanism under programmed control may be used to reciprocate push rod70 after the manner clearly disclosed in U.S. Pat. No. 3,478,419.Positioning posts 68 yield to the downward movement of push rod 70 andassist drive belt 50 in returning the working tool to the upper positionupon withdrawal of the push rod from engagement with the tool spindle.

in FIG. 7 is illustrated an alternate method of releasably retaining thetools in the non-working tool support position which includes a pair ofarcuately curved leaf springs 98 appropriately secured to the side wallsof the tool station forming slot. The leaf springs 98 would, of course,be duplicated in the upper and lower aligned slots defining a singletool support station.

For a completely manual operation, tool carrier 16 may be rotatedmanually as by gripping the same and rotating it through 90 to changetools. During such manual manipulation the motor 90 would, of course, bedeenergized with its rotor simply being rotated by virtue of the gearedengagement between rack and pinion 88, 92. Alternatively, the motor andrack may be dispensed with for those installations not requiringsemiautomatic or automatic operation. In either event it will be clearthat precise positionment of the carrier is not critical since the largebias exerted by drive belt 50 on the working tool will force the sameinto axial coincidence with the axis of tool rotation defined by Veebearing'14 provided only that the rotation of carrier 16 brings the nextworking tool in such juxtaposition to bearing 14 that it engages eitherof the Vee forming surfaces thereof. This is an important considerationwhere small and microtools are concerned since if the bearing itselfwere moved one could not be assured that each successive tool would bepositioned on the same unique work axis with the inherent likelihood oftool breakage.

it will be apparent that the tools positioned to either side of theworking tool act, in effect, as idlers for the recirculating drive belt.Consequently, each tool is rotating at full R.P.M. before and during itstransfer to the bearing so that those down times" previously associatedwith tool change operations due to the necessity of disrupting toolrotation are eliminated.

We claim:

I. A machining center, comprising; an open tool bearing defining an axisof tool rotation; a tool carrier including a plurality of tool stationseach comprising a releasable tool support means defining a tool supportaxis at each said station substantially parallel to said axis of toolrotation; means mounting said tool carrier for movement of said toolstations along a common uniform path adjacent said open bearing; andmeans for interchanging tools with said bearing as an incident of andduring said movement.

2. The machining center of claim 1 wherein the last named means includecam means.

3. The machining center of claim 2 wherein said cam means include atleast one cam surface positioned for engagement with tools supported atsaid stations and merging with the open portion of said bearing.

4. The machining center of claim 3 wherein each said tool support axisis fixed relative to said tool carrier for movement therewith along acommon uniform path adjacent said bearing; and said one cam surfaceintersects the common path of movement of the tool support axis wherebymovement of said tool carrier effects a camming engagement between toolssupported along said last named axes and said one cam surface forcamming tools into bearing engagement with said open bearing.

5. The machining center of claim 4 wherein said cam means includes camsurfaces positioned on opposite sides of and merging with the openportion of said bearing; and said cam means intersecting the common pathof movement of said tool support axes on opposite sides of said bearing.

6. The machining center of claim 5 wherein said open bearing is defined,at least in part, by cam surfaces integral therewith; and said toolstations include tool engaging portions, in addition to said releasabletool support means, for imparting the movement of said carrier to toolspositioned at said tool support stations whereby movement of said toolcarrier results in at least a component of said movement being impartedto tools supported at said tool support stations during the toolinterchange operation.

7. The machining center of claim 6 including means independent of saidreleasable tool support means for maintaining a tool at each saidstation.

8. The machining center of claim 7 wherein said last named meansincludes, at least in part, recirculating drive means.

9. The machining center of claim 8 wherein said recirculating drivemeans comprises an elastic recirculating drive member for accommodatingthe movement of tools into and out of said open bearing.

10. The machining center of claim 9 wherein said I open bearing is a Veebearing and said cam surfaces defining at least a part of said openbearing comprising the sides of said Vee bearing.

11. A machining center, comprising; an open bearing defining an axis oftool rotation; a tool carrier including a plurality of tool receivingopenings; releasable tool support means associated with said toolreceiving openings for supporting a tool in a non-working positionwithin the confines of each said tool receiving opening; means mountingsaid tool carrier for movement of said openings along a path adjacentsaid bearing; means for shifting a tool laterally of its own axis withinthe confines of each said opening between said non-working position anda working position on said bearing; means for urging the tools towardthe non-working position; and means for infeeding a working toolparallel to its own axis.

12. The machining center of claim 11 wherein said open bearing is a Veebearing; and said means for shifting a tool laterally of its own axiscomprises cam means.

13. The machining center of claim 11 wherein said releasable toolsupport means include magnet means.

14. The machining center of claim 11 wherein said releasable toolsupport means include resilient means.

15. The machining center of claim 11 wherein said tool carrier is arotary tool carrier and said tool receiving openings comprise slotsextending inwardly from the periphery thereof; and said releasable toolsupport means mounted adjacent the inner ends of said slots.

16. The machining center of claim 11 including tools positioned in atleast two of said openings; and said means for urging the tools towardthe non-working position comprising a tensioned flexible drive member indriving engagement with said tools; and means for driving said flexibledrive member.

17. A method of changing tools, comprising; supporting a plurality oftools in a tool carrier for arcuate movement adjacent a tool bearingabout an axis spaced from and parallel to the axis of each of saidplurality of tools; moving said carrier about said axis; camming one ofsaid tools laterally of its own axis out of said bearing; and cumminganother of said tools laterally of its own axis into said bearing.

1. A machining center, comprising; an open tool bearing defining an axisof tool rotation; a tool carrier including a plurality of tool stationseach comprising a releasable tool support means defining a tool supportaxis at each said station substantially parallel to said axis of toolrotation; means mounting said tool carrier for movement of said toolstations along a common uniform path adjacent said open bearing; andmeans for interchanging tools with said bearing as an incident of andduring said movement.
 2. The machining center of claim 1 wherein thelast named means include cam means.
 3. The machining center of claim 2wherein said cam means include at least one cam surface positioned forengagement with tools supported at said stations and merging with theopen portion of said bearing.
 4. The machining center of claim 3 whereineach said tool support axis is fixed relative to said tool carrier formovement therewith along a common uniform path adjacent said bearing;and said one cam surface intersects the common path of movement of thetool support axis whereby movement of said tool carrier effects acamming engagement between tools supported along said last named axesand said one cam surface for camming tools into bearing engagement withsaid open bearing.
 5. The machining center of claim 4 wherein said cammeans includes cam surfaces positioned on opposite sides of and mergingwith the open portion of said bearing; and said cam means intersectingthe common path of movement of said tool support axes on opposite sidesof said bearing.
 6. The machining center of claim 5 wherein said openbearing is defined, at least in part, by cam surfaces integraltherewith; and said tool stations include tool engaging portions, inaddition to said releasable tool support means, for imparting themovement of said carrier to tools positioned at said tool supportstations whereby movement of said tool carrier results in at least acomponent of said movement being imparted to tools supported at saidtool support stations during the tool interchange operation.
 7. Themachining center of claim 6 including means independent of saidreleasable tool support means for maintaining a tool at each saidstation.
 8. The machining center of claim 7 wherein said last namedmeans includes, at least in part, rEcirculating drive means.
 9. Themachining center of claim 8 wherein said recirculating drive meanscomprises an elastic recirculating drive member for accommodating themovement of tools into and out of said open bearing.
 10. The machiningcenter of claim 9 wherein said open bearing is a Vee bearing and saidcam surfaces defining at least a part of said open bearing comprisingthe sides of said Vee bearing.
 11. A machining center, comprising; anopen bearing defining an axis of tool rotation; a tool carrier includinga plurality of tool receiving openings; releasable tool support meansassociated with said tool receiving openings for supporting a tool in anon-working position within the confines of each said tool receivingopening; means mounting said tool carrier for movement of said openingsalong a path adjacent said bearing; means for shifting a tool laterallyof its own axis within the confines of each said opening between saidnon-working position and a working position on said bearing; means forurging the tools toward the non-working position; and means forinfeeding a working tool parallel to its own axis.
 12. The machiningcenter of claim 11 wherein said open bearing is a Vee bearing; and saidmeans for shifting a tool laterally of its own axis comprises cam means.13. The machining center of claim 11 wherein said releasable toolsupport means include magnet means.
 14. The machining center of claim 11wherein said releasable tool support means include resilient means. 15.The machining center of claim 11 wherein said tool carrier is a rotarytool carrier and said tool receiving openings comprise slots extendinginwardly from the periphery thereof; and said releasable tool supportmeans mounted adjacent the inner ends of said slots.
 16. The machiningcenter of claim 11 including tools positioned in at least two of saidopenings; and said means for urging the tools toward the non-workingposition comprising a tensioned flexible drive member in drivingengagement with said tools; and means for driving said flexible drivemember.
 17. A method of changing tools, comprising; supporting aplurality of tools in a tool carrier for arcuate movement adjacent atool bearing about an axis spaced from and parallel to the axis of eachof said plurality of tools; moving said carrier about said axis; cammingone of said tools laterally of its own axis out of said bearing; andcamming another of said tools laterally of its own axis into saidbearing.